JP6731334B2 - Ultrasonic cleaner and automatic analyzer using the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to an ultrasonic cleaning device for cleaning a nozzle for dispensing a sample such as serum or urine, and an automatic analyzer for performing component analysis by mixing a sample with a reagent.

In the automatic analyzer, a sample is dispensed by repeatedly using the same nozzle, and therefore, the tip of the nozzle is washed before sucking another sample. If the nozzle tip is not sufficiently washed, the previous sample component is brought into the next sample (carry over), and the measurement accuracy deteriorates. However, since an automatic analyzer having a high throughput performance performs a dispensing process at a high speed, it is not possible to use a sufficient time for cleaning the nozzle. Patent Document 1 discloses that an ultrasonic cleaner equipped with a Langevin transducer at the bottom of a cleaning tank is used to remove sample deposits on a nozzle by cavitation generated in a liquid.

JP-A-4-169850

In a cleaning device using ultrasonic waves, the drive frequency of the ultrasonic vibrator is often set to a low frequency (20 to 100 kHz) for dirt that is difficult to remove. Cleaning at low frequency uses cavitation generated in the liquid (a phenomenon in which bubbles are generated and disappeared due to a pressure difference generated in the liquid). However, the cavitation does not occur uniformly in the liquid, and the strength of the cavitation changes depending on the strength of the ultrasonic wave. In the region where the ultrasonic wave intensity is strong, the interval generated varies depending on the driving frequency, and there is a region where the cavitation is strong for each distance obtained by dividing the sound velocity of liquid (about 1500 m/s in water) by the driving frequency of the ultrasonic transducer. .. For example, when driven at 50 kHz, a standing wave with one wavelength of 30 mm (λ) is generated, and regions with strong cavitation strength are generated at intervals of 15 mm (λ/2) which is a half wavelength thereof. Further, the vicinity of the vibrating surface that generates ultrasonic waves is also a region where the cavitation strength is strong.

Therefore, in the ultrasonic cleaning device including the Langevin vibrator at the lower part of the cleaning tank as in Patent Document 1, when driving at 20 to 100 kHz to obtain the effect of cavitation, the region where cavitation becomes strong is 7.5 mm (100 kHz). Drive) to 37.5 mm (20 kHz drive) interval. The cavitation strength is stronger as it is closer to the drive source oscillator. Further, since the range of the region where cavitation is strong is narrow, the cleaning range of the nozzle is limited and cleaning unevenness is likely to occur. Further, in the ultrasonic cleaner having a structure in which the vibrator is provided in the lower portion of the cleaning tank, ultrasonic waves are generated in the liquid inside by vibrating the bottom of the stainless steel tank with the vibrator, so that the area of the bottom is increased. Further, in order to generate a standing wave, a liquid level of at least 7.5 mm (λ/4) is required. That is, since the conventional ultrasonic cleaner has a large bottom area and a high height, there is a problem that the amount of cleaning liquid required to generate a standing wave and perform effective cleaning is large. In particular, in an apparatus in which the carryover of a sample is a problem, it is necessary to replace the cleaning liquid every time the nozzle is cleaned to prevent the sample from reattaching to the nozzle. Therefore, a small amount of the cleaning liquid is desired.

For this reason, in addition to the configuration of the vibrating portion that can clean the nozzle tip (especially the outer circumference) in the drive frequency range of 20 to 100 kHz, ultrasonic waves including a cleaning tank that generates a standing wave in the liquid even at a low liquid level A washing machine and an automatic analyzer using the washing machine are provided.

According to the ultrasonic cleaner of the first aspect of the present invention, the cleaning tank for accumulating the cleaning liquid, the ultrasonic vibrator, and the cylindrical hole extending from the ultrasonic vibrator toward the cleaning tank and having the longitudinal direction in the vertical direction. The ultrasonic vibrator has a cylindrical vibrating head, and an air layer or a metal member provided at least in a region where the vibrating head is vertically projected under the cleaning tank. It is driven at a frequency that resonates in a vibration mode involving deformation in the longitudinal direction of the hole and a direction perpendicular to the longitudinal direction, and at least the region of the bottom of the cleaning tank where the vibrating head is projected vertically has resin as the main component. The height of the cleaning liquid made of the material and stored in the cleaning tank is shorter than 1/4 of the wavelength required by the frequency for driving the ultrasonic transducer and the sound velocity.

According to the ultrasonic cleaning device of the second invention, the cleaning tank for accumulating the cleaning liquid, the ultrasonic vibrator, and the cylindrical hole extending from the ultrasonic vibrator toward the cleaning tank and having the longitudinal direction in the vertical direction. The ultrasonic vibrator is driven at a frequency at which the vibrating head resonates and vibrates, and the cleaning tank is partially or wholly made of a resin-based material. Vibration of the ultrasonic wave generated by the resonant vibration of the vibrating head through the cleaning tank part made of a material whose main component is resin, in the deformation direction of the vibrating head when the vibrating head resonates and vibrates. An air layer or a metal member is provided at a distance that is an integral multiple of 1/4 of a wavelength obtained from the frequency for driving the ultrasonic transducer and the speed of sound from the antinode region.

Further, it is an automatic analyzer equipped with the ultrasonic cleaner according to the first invention or the second invention.

According to the first aspect of the present invention, by providing the mechanism for promoting the vibration in the Z direction of the vibrating head that resonates and vibrates in the secondary vibration mode, a high cleaning effect is realized while reducing the amount of cleaning liquid.

According to the second aspect of the present invention, a high cleaning effect is realized by reducing the vibration load at the time of resonance vibration of the vibrating head.

It is an automatic analyzer (top view) equipped with an ultrasonic cleaner. It is a structural example of a reagent dispensing mechanism. It is a structural example of a sample dispensing mechanism. It is an example of composition of a control part. It is a perspective view of an ultrasonic cleaner. It is a top view of an ultrasonic cleaner. It is sectional drawing of the ultrasonic cleaner along A-A'. It is a side view of an ultrasonic transducer and a vibrating head. It is a figure which shows the deformation|transformation of the vibrating head in a primary vibration mode. It is a figure which shows the deformation|transformation of the vibrating head in a secondary vibration mode. It is an impedance waveform of the ultrasonic transducer which attached the vibrating head. It is a schematic diagram of a cross section of a vibrating head of an ultrasonic cleaner and a cleaning tank. It is a figure for explaining a generating condition of a standing wave. This is an example in which a hole is provided at the bottom of the cleaning tank. It is a perspective view of the cleaning tank which provided the slope hole in the bottom part. It is a top view of the cleaning tank which provided the slope hole in the bottom part. It is sectional drawing which followed the B-B' of the washing tank which provided the slope hole in the bottom part. This is an example in which a cover is provided on the upper surface of the cleaning tank. It is an example of a piping configuration of an ultrasonic cleaner.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1A is a diagram showing the configuration of the automatic analyzer according to the present embodiment. The automatic analyzer 10 includes a reagent disk 12 in which a plurality of reagent containers 11 are mounted, a reaction disk 13 in which a reagent and a sample are mixed in a reaction cell 25, and the resulting reaction is measured, and a reagent for sucking and discharging the reagent. It has a dispensing mechanism 14 and a sample dispensing mechanism 15 for sucking and discharging a sample.

The reagent dispensing mechanism 14 includes a reagent nozzle 21 for dispensing a reagent (FIG. 1B), and the sample dispensing mechanism 15 includes a sample nozzle 22 for dispensing a sample (FIG. 1C). The sample loaded into the apparatus is loaded in a rack 24 and transported while being placed in a sample container (test tube) 23. A plurality of sample containers 23 are mounted on the rack 24. The sample is a blood-derived sample such as serum or whole blood, or urine.

The sample dispensing mechanism 15 includes a suction position for sucking the sample from the sample container 23, a discharge position for discharging the cell 25, a cleaning position for cleaning the tip of the nozzle 22 with the ultrasonic cleaner 26, and an ultrasonic cleaner 26. By cleaning, the nozzle 22 is moved to the cleaning tank 27 by a rotating operation in order to wash away the tip of the nozzle 22 to which the cleaning liquid is attached with water. Further, the sample dispensing mechanism 15 lowers the nozzle 22 according to the heights of the sample container 23, the reaction cell 25, the ultrasonic cleaner 26, and the cleaning tank 27 at the suction position, the discharge position, and the cleaning position, respectively. In order to perform such an operation, the sample dispensing mechanism 15 is configured to move the nozzle 22 to a target position and move it up and down. In this embodiment, the ultrasonic cleaner 26 is provided to clean the nozzle 22 of the sample dispensing mechanism 15, but an ultrasonic cleaner may be provided to clean the nozzle 21 of the reagent dispensing mechanism 14. Good.

The automatic analyzer 10 has a measurement unit 29, and measures the concentration of a predetermined component in the sample by measuring the liquid mixture of the sample and the reagent contained in the reaction cell 25. The measurement unit 29 has, for example, a light source and a photometer (such as an absorption altimeter or a scattering altimeter). The control unit 28 controls the movement of the nozzle, the suction/discharge control of the sample, the control of the liquid supply to the cleaning tank 27, the drive control of the ultrasonic cleaning device 26, and the control of various other mechanisms. Further, the automatic analyzer includes an operation unit (PC, control board, etc.) for operating the apparatus, and an apparatus including a unit for the inspection engineer to load and collect the rack 24, which are omitted in FIG. 1A. ..

FIG. 1D is a configuration example of the dispensing mechanism of the automatic analyzer 10 and the controller 28 of the cleaning device. The operation screen of the automatic analyzer 10 includes a device operation/display unit 600, which includes an analysis execution operation unit 601 for executing an inspection and a washer state display unit 602 for displaying the state of the ultrasonic washer 26. Have. The control unit 28 for controlling the device receives a command from the device operation/display unit 600 from the higher-level communication processing unit 611, and the device sequence processing unit 612 uses the sequence data of the sequence database 613 to dispense the dispensing mechanism 15 and ultrasonic waves. The cleaning device 26 is controlled.

The dispensing mechanism control unit 614 rotates the dispensing mechanism 15 and moves up and down through the motor control unit 615 and the motor drive unit 616 to move the nozzle 22. The cleaning device control unit 617 controls the ultrasonic wave driving unit (amplifier for piezoelectric element) 619 via the ultrasonic wave control unit 618 to drive the ultrasonic vibrator 205 provided in the ultrasonic cleaning device 26 (turn on the ultrasonic wave. /OFF). Since the resonance characteristic of the ultrasonic transducer 205 changes due to heat generation, the frequency adjusting unit 620 changes the drive frequency according to the change in the resonance frequency.

Further, the cleaning device control unit 617 sends an instruction to the pump control unit 621, and the pump drive unit 622 drives the pump connected to the cleaning tank of the ultrasonic cleaning device 26 to control the exchange of cleaning liquid and the like.

A configuration example of the ultrasonic cleaner 26 will be described with reference to FIGS. 2A to 2D. 2A is a perspective view of the ultrasonic cleaner 26, FIG. 2B is a top view, FIG. 2C is a cross-sectional view taken along line AA′ (FIG. 2B), and FIG. 2D is a side view of the ultrasonic transducer and the vibrating head. ..

The ultrasonic cleaner 26 includes one or more piezoelectric elements 203 sandwiched between the front mass 201 and the back mass 202, and the ultrasonic vibrator configured by fastening the front mass 201 and the back mass 202 with bolts 204 ( The base unit 207 is provided with a bolt-clamped Langevin Type Transducer (BLT) 205, a vibrating head 209, and a cleaning tank 206 for storing cleaning liquid. Here, the axial direction of the bolt 204 of the ultrasonic transducer 205 is the X direction, the direction perpendicular to the X direction on the upper surface (horizontal plane) of the base portion 207 is the Y direction, and the direction perpendicular to the horizontal plane, that is, the vertical direction is the Z direction. It is defined.

The ultrasonic transducer 205 includes a flange portion 208 and is fixed to the base portion 207. In the figure, the flange portion 208 is fixed to the base portion 207 below, but a flange fixing member is also provided above the flange portion 208, and the flange portion 208 is connected by connecting the member and the base portion 207. It is desirable to evenly fix the entire circumference of. Further, rubber or the like may be put in a portion where the flange portion 208 and the base portion 207 are in contact with each other in order to prevent wear and noise of the flange portion 208 and the base portion 207.

A vibration head 209 extending toward the cleaning tank 206 is provided at the tip of the ultrasonic vibrator 205 on the front mass side. The tip portion 210 of the vibrating head 209 has a cylindrical shape, and is adjusted so as to come to a position where it does not contact the cleaning tank 206 and is immersed in the cleaning liquid stored in the cleaning tank 206. The cylindrical vibrating head tip portion 210 is provided with a cylindrical hole 211 having a diameter larger than the tip outer diameter of the nozzle 22. The front mass 201 and the vibrating head 209 may be separately manufactured and fixed with bolts or the like, or may be integrally manufactured. Further, the cleaning tank 206 is provided with a pipe 212 for supplying the cleaning liquid, and by supplying a fixed amount of the cleaning liquid, the cleaning liquid in the cleaning tank 206 can be replaced by overflowing. That is, the cleaning liquid supplied from the cleaning liquid supply pipe 212 overflows from the upper end of the side wall of the cleaning tank 206, flows into the liquid receiver 213 on the outer periphery of the cleaning tank 206, and is discharged from the drainage path 214, whereby the cleaning tank 206. The height (liquid level) of the inside cleaning liquid becomes constant every time the cleaning liquid is supplied.

Although it is necessary to exchange the cleaning liquid in a short time in order not to reduce the throughput of the apparatus, if the cleaning liquid is supplied at a high speed, the cleaning liquid may be jetted and scattered around the ultrasonic cleaning device 26. By positioning the cleaning liquid supply pipe 212 below the vibrating head tip 210, the supplied cleaning liquid hits the vibrating head tip 210 even when the cleaning liquid is supplied at a high speed, thereby suppressing the flow velocity in the cleaning tank 206. Prevents liquid from splashing. On the contrary, when the cleaning liquid is supplied from above the cleaning tank 206 (that is, above the liquid surface), the air mixes and the cleaning liquid foams. Therefore, it is desirable to supply the liquid in the cleaning tank 206. Further, when the pipe 212 is provided on the side wall of the cleaning tank 206 and the cleaning liquid is supplied so as to be applied to the vibrating head tip portion 210, the same effect as when the vibrating head tip portion 210 is positioned can be obtained, while the vibrating head tip portion 210 can be used for the front mass. When the cleaning liquid is pushed up toward the 201 side, the components of the cleaning liquid may be collected in the connecting portion between the front mass 201 and the vibrating head 209, which may cause contamination. Therefore, in supplying the cleaning liquid, it is desirable to supply the cleaning liquid from the lower portion of the vibrating head tip portion 210 as shown in FIG. However, if it is not a cleaning liquid but a liquid such as water that does not cause a problem of adhesion or scattering, it may be supplied from above the cleaning tank 206 or from the side wall. In particular, when cleaning the vibrating head 209 for maintenance, it is effective to provide a pipe separately from the cleaning liquid supply pipe 212 on the side surface to supply water. Such a configuration will be described later with reference to FIG.

Although the drawing shows an example in which the liquid receiver 213 is provided so as to come into contact with the entire circumference of the cleaning tank 206, in this embodiment, since the cleaning liquid accumulated in the cleaning tank 206 can be reduced, the replacement of the cleaning liquid can be shortened accordingly. Can be done in. For this reason, a notch is provided in a part of the side wall of the cleaning tank 206 so that the cleaning liquid flows out only from the side wall having a reduced height. It is also possible to reduce the size by forming the shape in contact with a certain side wall portion. This has the effect of making the base portion 207 of the ultrasonic cleaner 26 smaller.

Although not shown, an electrode (for example, a copper plate) is sandwiched between the metal block (201/202) and the piezoelectric element 203 and between the plurality of piezoelectric elements 203, and a sine wave voltage having a predetermined frequency is applied to these electrodes. Is applied, the ultrasonic transducer 205 is driven in the axial direction of the bolt 204. In particular, it is known that the amplitude generated by the piezoelectric element 203 can be amplified by making the shape of the front mass 201 into a horn shape (a shape in which the diameter is changed between the piezoelectric element 203 side and the vibrating head side). By designing the length and shape according to the frequency to be driven, a large amplitude can be obtained with less power. Although a conical horn shape is shown in the figure, other shapes (exponential horn, etc.) are also acceptable.

Further, by providing an elongated vibrating head 209 at the tip of the horn-shaped front mass 201 and resonating in synchronization with the vibration of the ultrasonic transducer 205, a large displacement can be generated at the vibrating head tip 210. As a result, the electric energy applied to the ultrasonic transducer 205 can be efficiently converted into vibration (kinetic energy) of the vibrating head tip 210.

When cleaning the nozzle 22 with the ultrasonic cleaner 26, the piezoelectric element 203 is driven at a predetermined low frequency, and the nozzle 22 is cleaned in the cylindrical hole 211 of the vibrating head tip 210 (a range of about 5 mm from the tip of the nozzle 22). ) Is soaked and immersed in the cleaning liquid for a certain period of time to remove the dirt adhering to the outer peripheral portion of the nozzle 22 by cavitation. After cleaning, the nozzle 22 is pulled out from the ultrasonic cleaner 26, and the cleaning liquid in the cleaning tank 206 is replaced by an overflow, so that the next cleaning of the nozzle 22 can be performed with a new cleaning liquid, and carry-over is suppressed. You can These controls are executed by the control unit 28 according to a predetermined device sequence.

In this way, since the cleaning liquid can be cleaned if the cleaning liquid is present in the cylindrical hole 211 of the vibrating head tip 210 and its surroundings, the amount of the cleaning liquid used can be reduced. For example, with a thin nozzle having an outer diameter of 1.0 mm or less, cleaning can be performed with a cleaning liquid amount of 0.5 mL or less, and the size of the cleaning device can be reduced. Even if water is supplied to the cleaning tank 206 as a cleaning liquid and used, a high cleaning effect due to cavitation can be obtained. Therefore, water may be used depending on the target cleaning effect.

The ultrasonic cleaner 26 drives the piezoelectric element 203 at a frequency of 20 to 100 kHz suitable for generating cavitation in the cleaning liquid, resonates the vibrating head 209 in the cleaning tank 206, and vibrates the large displacement (frequency). Is the same as the driving frequency) and generates ultrasonic vibration. As a result, cavitation occurs around the vibrating head 209, particularly around the antinode of vibration (the portion where the amplitude is greatest). Since the vibrating head tip 210, which is the open end, serves as an antinode of vibration, the tip of the nozzle 22 is intensively washed by the cavitation generated in the cylindrical hole 211.

The vibration of the vibrating head 209 will be described with reference to FIGS. The vibrating head 209 has a plurality of vibration modes depending on how it is deformed due to resonance vibration. 3A shows the deformation of the vibrating head 209 in the primary vibration mode, FIG. 3B shows the deformation of the vibrating head 209 in the secondary vibration mode, and FIG. 3C shows the impedance waveform of the ultrasonic transducer to which the vibrating head is attached.

There are a plurality of resonance frequencies of the vibrating head 209, and different deformations occur at the time of resonance. FIG. 3A shows a first-order vibration mode, in which the vibrating head tip 210 shakes in the X direction. FIG. 3B shows the secondary vibration mode, in which the vibrating head tip portion 210 swings in the X direction, and a vibration node (a portion where the vibration is minimized) is formed in the middle of the vibrating head tip portion 210, and the vertical direction (Z direction). ) Is a vibration mode. In the figure, the deformation is exaggerated in order to make it easier to understand the difference between the vibration modes.

FIG. 3C is a diagram showing frequency on the horizontal axis and impedance on the vertical axis. A resonance point 410 of the vibrating head 209 and a resonance point 411 of the ultrasonic transducer 205 (a mode in which the ultrasonic transducer 205 expands and contracts in the axial direction of the bolt 204) are shown. The resonance point 410 may be a resonance point of the primary vibration mode or a resonance point of the secondary vibration mode, but it is a vibration mode used for cleaning, and its resonance frequency easily causes cavitation. Must be in the range -100 kHz. Further, it is desirable to design the vibrating head 209 and the ultrasonic transducer 205 so that the resonance point 410 and the resonance point 411 are close to each other and the absolute value of the difference between them is 10 kHz or less. This is because, by bringing the resonance points close to each other, the electric energy can be efficiently converted into the vibration of the vibrating head tip portion 210 by the interaction thereof.

FIG. 4 is a schematic view of a cross section of the vibration head 209 and the cleaning tank 206 of the ultrasonic cleaning device of this embodiment. The vibrating head 209 vibrates at the resonance point of the secondary vibration mode, and has both X-direction vibration and Z-direction vibration. As described above, the vibrating head tip 210 is located in the cleaning liquid in the cleaning tank 206, and the nozzle 22 is inserted into the cylindrical hole 211 to clean the nozzle 22. As a result, the nozzle 22 is cleaned by the cavitation generated near the inner wall of the cylindrical hole 211. When the vibrating head 209 vibrates ultrasonically, liquid rises 310 around the vibrating head 209, and the water level is partially higher than the edge of the cleaning tank 206. Therefore, if the position of the cylindrical hole 211 is close to the neck of the vibrating head 209 (the portion of the vibrating head 209 that extends in the Z direction between the front mass 201 and the vibrating head tip portion 210), during cleaning. The range in which the nozzle 22 is exposed to the cleaning liquid expands, and for example, the set range of 5 mm wets up to 7 mm. When other than water is used as the cleaning liquid, it is necessary to perform water cleaning on the cleaning portion of the nozzle 22 in order to drop the cleaning liquid, but it is necessary to expand the cleaning range in this water cleaning process. .. When the washing range is expanded, there are problems that the throughput is lowered and water easily remains in the nozzle 22 and the sample is diluted. Therefore, it is preferable that the head tip length 220 is set such that the position of the cylindrical hole 211 is separated from the neck of the vibrating head 209 so that the nozzle 22 does not come into contact with the liquid rising 310.

Further, in this embodiment, the cleaning tank 206 is made of a material (for example, resin) capable of transmitting ultrasonic waves generated in the cleaning liquid, and an air tank 301 for storing air is provided below the cleaning tank 206. It is fixed to the base portion 207 via the. The cleaning tank 206 may be entirely made of resin or a part thereof, but at least a region of the bottom of the cleaning tank 206 where the vibrating head tip 210 is projected in the vertical direction is made of resin. Similarly, the air tank 301 is also provided so as to cover at least the region where the vibrating head tip 210 is projected in the vertical direction. However, as described above, it is desirable that the cleaning liquid is supplied from below the cleaning tank 206, and therefore, in FIG. 4, a pipe 302 for supplying the cleaning liquid and a cleaning liquid supply pipe 212 are provided at the bottom of the cleaning tank 206. .. Therefore, the resin at the bottom of the cleaning tank 206 and the air tank 301 are arranged so as to surround the pipe 302. That is, in a cleaning device that does not supply a cleaning liquid or the like from the bottom surface of the cleaning tank 206, it is not necessary to make such a hole under the cleaning tank 206. When the entire cleaning tank 206 is made of resin, it may be integrally molded with the base portion 207. By manufacturing in this way, manufacturing cost can be reduced.

The height of the cleaning liquid stored in the cleaning tank 206 is defined as La. Since the cleaning liquid overflows and is supplied to the cleaning tank 206, the liquid is stored up to the upper end of the side wall of the cleaning tank 206. Therefore, the height La of the cleaning liquid stored in the cleaning tank is the height from the bottom surface of the cleaning tank to the upper end of the side wall (partial or entire circumference) of the cleaning tank in contact with the liquid receiver. If the thickness of the bottom of the cleaning tank 206 made of a material that can transmit the ultrasonic waves generated in the cleaning tank 206 is defined as Lb, the length L from the liquid surface to the air tank 301 is La+Lb. ..

Ultrasonic waves are generated in the cleaning liquid due to the vibration of the vibrating head tip portion 210. By providing the air tank 301, the ultrasonic waves generated by the vibration in the Z direction travel in the Z direction, but L is a predetermined condition. When the above condition is satisfied, a standing wave is generated in the Z direction within the cleaning tank 206 by repeating reflection on the liquid surface and the air layer of the air tank 301. The vibration amplitude of the vibrating head 209 was compared between the resin cleaning tank A having the structure shown in FIG. 4 in which the standing wave is generated in the Z direction and the resin cleaning tank B without the air tank 301. In A, the vibration amplitude of the vibrating head 209 was larger. Further, as a result of comparing the cleaning effect between the cleaning tank A and the cleaning tank B by using the vibration head 209 having the same shape, the cleaning effect obtained by using the cleaning tank A was higher.

This result is considered to be due to the following reasons. The cleaning liquid has viscosity, and the cleaning liquid becomes a vibration load against the vibration of the vibrating head. When the nozzle 22 is cleaned by the cavitation generated in the vicinity of the inner wall of the cylindrical hole 211 as in the present embodiment, it is mainly the vibration in the X direction that contributes to the generation of the cavitation. However, in the secondary vibration mode, the vibrating head 209 resonates not only in the X direction but also in the Z direction. When the vibration in the Z direction is suppressed by the cleaning liquid, the vibration in the X direction is also suppressed. By generating a standing wave in the Z direction in the cleaning tank 206, the vibration load is reduced with respect to the vibration of the vibrating head tip portion 210 in the Z direction, the vibration in the Z direction becomes large, and the vibration in the X direction also occurs. , More amplified than when no standing wave is generated.

The conditions for generating a standing wave will be described with reference to FIG. The vertical axis of FIG. 5 represents the amplitude of the wave, and the horizontal axis represents the depth from the liquid surface. Further, the waveform 401 is a waveform when traveling in the liquid, and the waveform 402 is a waveform when traveling in the resin. The condition for generating the standing wave is L=(λ/4)×n (λ: 1 wavelength of ultrasonic wave, n: integer). The wavelength of the ultrasonic wave varies depending on the medium in which the ultrasonic wave travels, and the wavelength of the liquid is λa and the wavelength of the resin (between the bottom surface of the cleaning tank 206 and the air tank 301) is λb. Further, the wavelength of liquid and resin is a value obtained by dividing the sound velocity determined by the material (about 1500 m/s for water, about 2000 m/s for resin depending on the type) by the driving frequency.

In order to generate a standing wave (n=1), the waveform 401 is used up to the depth La and the waveform 402 is used from the depth La to L (=La+Lb). Just set the length. That is, if the ultrasonic wave travels up to the depth La by the ratio α of the quarter wavelength of the ultrasonic wave,
La=α×(λa/4)
Lb=(1-α)×(λb/4)
Can be expressed as Therefore, the minimum distance of Lb is calculated by Lb=(1-La/(λa/4))×(λb/4). Since L=La+Lb, the condition that the standing wave is generated can be adjusted by the distance Lb from the bottom surface of the cleaning tank 206 to the air tank 301. Therefore, the amount of liquid corresponding to the height of Lb can be reduced as compared with the case where a standing wave is generated by vibrating the bottom of the cleaning tank to adjust the liquid level. That is, the nozzle 22 can be strongly washed with a small amount of liquid. The values of λ and the like vary depending on the temperature change and may deviate from the design value of L=(λ/4)×n, but as long as the conditions close to the standing wave generation conditions are satisfied. A high cleaning effect can be obtained.

It should be noted that the resin may be a resin whose main component is a resin, and may be mixed with a material other than the resin, such as glass fiber for structural reinforcement. Also, an example in which the air layer of the air tank 301 is used as the ultrasonic wave reflecting material has been shown, but the same effect can be obtained by embedding a metal that reflects ultrasonic waves (for example, iron or stainless steel material) in the position of the air tank 301. Obtainable. That is, the reflectance of the material at the bottom of the cleaning tank 206 must be lower than the reflectance of a reflective material such as air or metal, and in order to suppress the loss, the reflectance of the material at the bottom of the cleaning tank 206. The lower the better, the better, and the higher the reflectance of the reflector, the better.

The reflectance between liquid (water) and a different medium is
Reflectance r=(X−Y) ² /(X+Y) ²
It can be represented by X: acoustic impedance of water, and Y: acoustic impedance of a medium (for example, resin or metal). The acoustic impedance is the product of the density of the medium and the speed of sound. That is, as the reflectance increases, the reflection at the boundary surface increases as the difference in acoustic impedance increases, so that the acoustic impedance ratio between the materials can be used as an index of the material used. The acoustic impedance X of water is about 1.5×10 ⁶ kg/m ² s. Although the acoustic impedance of resin varies depending on its composition, it is approximately 3×10 ⁶ kg/m ² s, which is on the same order as the acoustic impedance of water, and is a material that is easy to use. A gas such as air (about 430 kg/m ² s), which has an extremely low acoustic impedance, is particularly suitable as a reflector, but even if a metal material is used, its acoustic impedance (about 4 × 10 ⁷ kg/m ^{2 s)} Since s) is larger than the acoustic impedance of resin by one digit or more, it can be used.

Similarly, the speed of sound can be used as a simple index. In this case, the speed of sound of water is approximately 1500 m/s, whereas the speed of sound of resin is 2000 to 3000 m/s, which is less than double. On the other hand, it is possible to select a metal in which the speed of sound of air is about 330 m/s and the speed of sound of metal is 5000 m/s or more, which is, for example, twice or more the speed of sound of resin.

Although FIG. 4 shows an example in which the vibration load in the Z direction is reduced, it is also possible to reduce the vibration load in the X direction. That is, when the vibrating head 209 is operated in the primary vibration mode, the vibrating head 209 vibrates exclusively in the X direction. In such a case, the cleaning tank is designed so that a standing wave is generated in the X direction. By doing so, the vibration can be amplified in the X direction. In this case, the air tank 301 of FIG. 4 is not necessary, and the function of the air tank 301 as a reflecting material is fulfilled by the outside of the side wall of the cleaning tank, that is, the air layer of the liquid receiver 213. Further, the length La′ of the cleaning liquid in this case is from the end surface of the vibrating head 209 to the side surface (cleaning water side) of the cleaning tank 206, and is defined as the thickness Lb′ of the side wall of the cleaning tank 206.
L′=La′+Lb′=(λ/4)×n (λ: 1 wavelength of ultrasonic wave, n: integer)
Thus, the vibration load of the vibration in the X direction can be reduced and the vibration in the X direction can be amplified.

As described above, in this embodiment, the vibrating head resonates and vibrates through the cleaning tank portion made of a material having a resin as a main component with respect to the deformation direction of the vibrating head when the vibrating head resonates and vibrates. By providing an air layer or a metal member at a distance that is an integral multiple of 1/4 of the wavelength obtained by the frequency for driving the ultrasonic transducer and the speed of sound from the region that is the antinode of the vibration of the ultrasonic wave generated by The vibration load is reduced and a high cleaning effect is obtained.

The tip diameter of the nozzle 22 targeted in the present embodiment is as thin as 0.5 to 1.5 mm, the diameter of the cylindrical hole 211 is preferably 2 to 4 mm, and the washing range is 4 mm. The inner height (liquid level La) is about 6 mm, and when driven at 50 kHz, the thickness Lb from the bottom surface of the cleaning tank 206 to the air tank 301 is about 2 mm. As described above, the condition for generating the standing wave is L=(λ/4)×n. Therefore, if n is set to a large value, the length of Lb for generating the standing wave longer than 2 mm can be taken. However, when the distance that the ultrasonic waves propagate in the cleaning tank 206 becomes long, loss due to heat generation when the ultrasonic waves propagate through the bottom material of the cleaning tank 206 is likely to occur, and therefore the intensity of the reflected ultrasonic waves is Weaken. Therefore, it is desirable to set Lb to a short value. That is, it is desirable that n=1.

FIG. 6 shows an example in which holes are provided in the cleaning tank of the ultrasonic cleaning device of this embodiment. Since the ultrasonic cleaning device 26 mounted on the automatic analyzer 10 needs to replace the cleaning liquid each time the nozzle 22 is cleaned, it is desirable to perform cleaning with a small amount of cleaning liquid in order to suppress the consumption of the cleaning liquid. Therefore, by providing the hole 320 at the bottom of the cleaning tank 206 and allowing the nozzle 22 to move up and down inside the hole 320, it is possible to clean the target nozzle cleaning range with a smaller liquid level.

For example, in order to reduce the amount of cleaning liquid, the height of the vibrating head tip 210 is shortened, the water level La of the cleaning tank 206 is further lowered, or the nozzle 22 is cleaned regardless of whether or not the liquid amount is changed. The hole 320 may be provided when it is desired to widen the range. In the present embodiment, the vibrating head tip 210 amplifies the vibration by the standing wave in the cleaning tank 206. However, since there is not much ultrasonic wave propagation immediately below the cylindrical hole 211 of the vibrating head tip 210, the vibration head has a cylindrical shape. Even when the hole 320 is provided immediately below the hole 211, the vibration amplification effect of the vibration head 209 by the standing wave can be obtained as in the configuration of FIG. In order to clean the nozzle 22, a diameter of 2 to 4 mm, which is similar to that of the cylindrical hole 211, may be used, and the depth depends on the cleaning range of the nozzle. The depth may be 4 mm.

According to the device sequence of the control unit 28, when the sample dispensing mechanism 15 performs cleaning in the cleaning tank 206 having the hole 320 at the bottom, the nozzle 22 is inserted into the cylindrical hole 211 of the vibrating head tip 210, and the ultrasonic transducer is inserted. After driving 205 (the nozzle 22 may be inserted after driving the ultrasonic transducer 205), the nozzle 22 is moved up and down so that the cleaning range of the nozzle 22 enters the cylindrical hole 211. By moving the nozzle 22, it is possible to clean a wide range with a small amount of liquid. The control unit determines the order of whether to wash the tip side of the nozzle 22 first or the root side first. Further, for example, if it is known that dirt easily accumulates on the tip side of the nozzle 22, the cleaning time on the tip side of the nozzle 22 can be extended and the cleaning time on the root side can be shortened.

7A to 7C are examples in which an inclined hole is provided at the bottom of the cleaning tank 206. 7A is a perspective view of the cleaning tank 206, FIG. 7B is a top view, and FIG. 7C is a sectional view taken along line B-B′ (FIG. 7B). Similar to the embodiment of FIG. 6, in order to reduce the cleaning liquid, an inclined hole 501 whose bottom surface is inclined with respect to the bottom surface of the cleaning tank is partially provided at the bottom of the cleaning tank. It has an inclined hole 502 with the same inclination angle as the hole 501 (that is, the bottom surface 503 and the top surface 504 are in a parallel relationship). The ultrasonic waves generated by the vibration of the vibrating head tip 210 in the Z direction are transmitted through the cleaning tank 206 and reflected by the air layer in the inclined hole 502 on the rear surface of the cleaning tank. At this time, the reflection angle of the ultrasonic wave is determined by the inclination angle of the bottom surface 503 of the inclined hole 501. Therefore, by adjusting this inclination angle, the ultrasonic wave is generated in the cylindrical hole 211 of the vibrating head tip 210 above the inclined hole 501. Can be reflected. As a result, in addition to the ultrasonic waves generated by the vibration in the X direction, the ultrasonic waves generated by the vibration in the Z direction are also introduced into the cylindrical hole 211 of the vibrating head tip portion 210, so that the ultrasonic wave intensity in the cylindrical hole 211 is increased. As a result, the cavitation is concentrated and cavitation occurs intensively, so that a high cleaning effect can be obtained. For example, when the liquid level is 6 mm and the driving frequency is 50 kHz, ultrasonic waves can be effectively reflected on the vibrating head tip 210 with a plate thickness of 3 mm and an inclination angle of 15 degrees.

In this case, as the cleaning liquid length La″ along the axis perpendicular to the bottom surface 503 of the inclined hole 501 and the distance Lb″ between the inclined hole 501 and the inclined hole 502,
L″=La″+Lb″=(λ/4)×n (λ: 1 wavelength of ultrasonic wave, n: integer)
Set so that the relationship is established. Strictly speaking, since the bottom surface 503 of the inclined hole 501 and the water surface are not parallel to each other, the length of La″ is strictly different depending on the measurement position, but the difference of this degree can be ignored. The supply pipe is provided in a portion other than the inclined hole 501 and the inclined hole 502. Further, even if the lower portion of the inclined hole 502 is further covered with metal or resin, ultrasonic waves are reflected by the air in the inclined hole 502, The ultrasonic wave reflection function described above is not impaired, and a similar effect can be obtained by embedding a metal member at the same position as the upper surface 504 of the inclined hole 502 instead of the inclined hole 502.

FIG. 8 shows an example in which a cover is added to the upper surface of the cleaning tank 206. When the ultrasonic oscillator 205 is driven, the cleaning liquid may be scattered from the vibrating head 209 or the vibrating head tip portion 210 to the surroundings depending on the state of the liquid. Therefore, it is desirable to provide the cover 510 on the upper surface of the cleaning tank 206. When the cover 510 is installed at a position in contact with the cleaning liquid in the cleaning tank 206, the above-mentioned standing wave is generated under the condition that when the cover 510 is made of metal, the air tank 301 is removed from the surface of the cover 510 inside the cleaning tank 206. The distance up to is L, and it is necessary to design this L to be λ/4. By providing the cover 510 on the liquid surface, a standing wave is applied to the cleaning liquid in the cleaning tank 206 without being affected by the fluctuation of the liquid surface caused by the vibration of the vibrating head 209 and the change of the liquid level due to the rising of the liquid. Can occur.

The cover 510 needs a nozzle insertion port 512 for inserting the nozzle 22, but like the case where the hole 320 is provided at the bottom of the cleaning tank 206 in FIG. The upper part of the hole 211 is less affected by the reflection of ultrasonic waves, so that there is no problem even if a partial hole is provided. Further, since the hole provided for overflowing the cleaning liquid is provided at a position that does not overlap the vibrating head tip portion 210, it does not affect the reflection of ultrasonic waves. Since it reflects on the air surface, the cover 510 can be made of resin.

FIG. 9 is an example of a piping configuration of the ultrasonic cleaner 26. The cleaning tank 206 has a pipe 302 for supplying a cleaning liquid and a pipe 701 for discharging water for maintenance of the cleaning device, each of which is connected to a tube 703 via a connecting portion 702. The tube 703 is made of a chemical-resistant material that can also be used for supplying the cleaning liquid, and is connected to the plurality of electromagnetic valves 704, the switching valve 705, and the syringe pump 706. The cleaning liquid is stored in the cleaning liquid tank 707 and needs to be replenished periodically, although it depends on the frequency of use of the ultrasonic cleaning device 26. Water is stored in the reservoir tank 708, but is automatically replenished by connecting it to the pipe 709 for connecting to clean water.

The ultrasonic cleaner 26 having the above-described piping replaces the cleaning liquid in the cleaning tank 206 by overflow before and after cleaning the nozzle 22. Therefore, after the switching valve 705 is switched to the cleaning liquid side pipe, the cleaning liquid is drawn from the cleaning liquid tank 707 into the tube 703 by performing the operation of closing the electromagnetic valve 704a and closing the electromagnetic valve 704b to make the syringe pump 706 a negative pressure. .. Then, the solenoid valve 704a is opened, the solenoid valve 704b is closed, and the syringe pump 706 is operated to a positive pressure to push the washing liquid in the tube 703 into the washing tank 206. By the above operation, a new cleaning liquid is supplied into the cleaning tank 206, and the cleaning liquid in the cleaning tank 206 can be discharged and replaced by overflow. Similarly, when water is supplied into the cleaning tank 206, the switching valve 705 is switched to the water side pipe, and water is supplied into the cleaning tank 206 by opening/closing the solenoid valves 704c and 704d and operating the syringe pump 706. it can. As described above, water and the cleaning liquid can be supplied into the cleaning tank 206 by the operation of one syringe pump 706.

When the automatic analyzer 10 is inspecting the sample, the cleaning of the nozzle 22 is repeated, and the cleaning liquid replacement operation is repeated in a short time. Therefore, the switching valve 705 is switched to the cleaning liquid side pipe. .. Before the automatic analyzer 10 finishes the inspection process of the sample and enters the standby state, the switching valve 705 is switched to the water side pipe, and a certain amount of water is discharged toward the vibrating head 209, so that the vibrating head 209 is discharged. The adhered cleaning liquid and dirt can be washed away, and the cleaning liquid can be prevented from depositing due to drying, which eliminates the need for manual maintenance. Further, it is also possible to replace the cleaning liquid in the cleaning tank 206 with water when it is not used for a certain period of time (for example, a holiday without inspection). Such control is also performed by the control of the device sequence processing unit 612 of the control unit 28 illustrated in FIG. 1D.

According to the ultrasonic cleaning device 26 described above, a standing wave is generated at a low liquid level due to ultrasonic reflection between the liquid surface of the cleaning tank 206 made of a material that transmits ultrasonic waves and the reflective material such as the air tank 301. By making it possible to amplify the vibration of the vibrating head 209, it is possible to intensively generate cavitation in the cleaning liquid and effectively clean the nozzle 22. This makes it possible to provide an inspection device and an analysis device with high inspection accuracy without carrying over another sample attached to the nozzle 22.

In the present embodiment, the sample dispensing of the biochemical automatic analyzer was described as an example, but the ultrasonic cleaner of the present invention has a reagent dispensing nozzle and a dispensing nozzle of the immuno-automatic analyzer such as other clinical testing devices. Similarly, the dispensing nozzle can be cleaned.

10: automatic analyzer, 11: reagent container, 12: reagent disc, 13: reaction disc, 14: reagent dispensing mechanism, 15: sample dispensing mechanism, 21: reagent nozzle, 22: sample nozzle, 23: sample Container, 24: sample rack, 25: reaction cell, 26: ultrasonic cleaner, 27: cleaning tank, 28: control unit, 29: measuring unit, 201: front mass, 202: back mass, 203: piezoelectric element, 204 : Bolt, 205: Ultrasonic transducer (Bolting Langevin transducer), 206: Cleaning tank, 207: Base portion, 208: Flange portion, 209: Vibrating head, 210: Vibrating head tip portion, 211: Cylindrical hole, 212 : Cleaning liquid supply pipe, 213: liquid receiver, 214: drainage channel, 220: vibrating head tip length, 301: air tank, 302: liquid supply pipe, 310: rising of liquid, 320: hole, 401: waveform, 402 : Waveform, 410: Resonance point of vibrating head, 411: Resonance point of ultrasonic transducer, 501: Inclined hole at bottom of cleaning tank, 502: Inclined hole at back of cleaning tank, 503: Bottom surface of inclined hole 501, 504: Inclined Top surface of hole 502, 510: cover, 512: nozzle insertion port, 600: device operation/display unit, 601: analysis execution operation unit, 602: washer state display unit, 611: upper communication processing unit, 612: device sequence processing Part, 613: sequence database, 614: dispensing mechanism control part, 615: motor control part, 616: motor drive part, 617: washer control part, 618: ultrasonic control part, 619: ultrasonic drive part, 620: Frequency adjustment unit, 621: Pump control unit, 622: Pump drive unit, 701: Water discharge pipe, 702: Connection unit, 703: Tube, 704: Solenoid valve, 705: Switching valve, 706: Syringe pump, 707: Washing liquid Tank, 708: reservoir tank, 709: clean water connection pipe.

Claims (15)

A cleaning tank for collecting cleaning liquid,
Ultrasonic transducer,
A vibrating head that extends from the ultrasonic vibrator toward the cleaning tank, and has a cylindrical hole having its longitudinal direction in the vertical direction at its tip.
Under the cleaning tank, at least an air layer or a metal member provided in a region where the vibrating head is projected in the vertical direction,
The ultrasonic transducer is driven at a frequency at which the vibrating head resonates in a vibration mode accompanied by deformation of the cylindrical hole in the longitudinal direction and a direction perpendicular to the longitudinal direction,
Of the bottom of the cleaning tank, at least the region in which the vibrating head is projected in the vertical direction is made of a material having a resin as a main component,
The height of the cleaning liquid stored in the cleaning tank is shorter than 1/4 of the wavelength required by the frequency for driving the ultrasonic transducer and the speed of sound. In claim 1,
The sum of the height of the cleaning liquid stored in the cleaning tank and the distance from the bottom surface of the cleaning tank to the air layer or the metal member is 1/wavelength obtained by the frequency driving the ultrasonic transducer and the speed of sound. Ultrasonic cleaner set as an integer multiple of 4. In claim 2,
Having a liquid receiver in contact with part or all of the side wall of the cleaning tank,
The height of the cleaning liquid stored in the cleaning tank is determined by the height from the bottom surface of the cleaning tank to the upper end of the side wall of the cleaning tank in contact with the liquid receiver. In claim 3,
A pipe for supplying a cleaning liquid to the cleaning tank,
The pipe is opened in a region where the vibrating head is vertically projected on the bottom surface of the cleaning tank.
The ultrasonic cleaner in which the air layer or the metal member is disposed around the pipe. In claim 2,
An ultrasonic cleaner in which a hole is provided in a region in which the cylindrical hole of the tip portion of the vibrating head is vertically projected on the bottom surface of the cleaning tank. In claim 2,
In the bottom surface of the cleaning tank, the bottom surface has an inclined hole inclined with respect to the bottom surface of the cleaning tank,
An ultrasonic cleaner having an air layer having an upper surface parallel to the bottom surface of the inclined hole or a metal member provided along the surface parallel to the bottom surface of the inclined hole under the inclined hole. In claim 4,
An ultrasonic cleaner having a pipe for supplying water for cleaning the cleaning tank to a side surface of the cleaning tank. In claim 4,
A cover provided on the upper end of the side wall of the cleaning tank,
An ultrasonic cleaner in which a hole for overflowing the cleaning liquid is provided in the cover at a position where it does not overlap the tip of the vibrating head. A cleaning tank for collecting cleaning liquid,
Ultrasonic transducer,
A vibrating head that extends from the ultrasonic transducer toward the cleaning tank, and has a cylindrical hole having its longitudinal direction in the vertical direction at its tip.
The ultrasonic transducer is driven at a frequency at which the vibrating head resonates and vibrates,
The cleaning tank is partly or wholly made of a material having a resin as a main component,
Ultrasonic waves generated by resonant vibration of the vibrating head through a cleaning tank portion made of a material containing the resin as a main component with respect to a deformation direction of the vibrating head when the vibrating head resonates and vibrates. An ultrasonic cleaner having an air layer or a metal member at a distance that is an integral multiple of 1/4 of the wavelength obtained from the frequency for driving the ultrasonic vibrator and the speed of sound from the region serving as the antinode of the vibration. In claim 9,
Having a liquid receiver in contact with a part or the whole circumference of a side wall made of a material containing the resin as a main component of the cleaning tank,
The ultrasonic transducer is driven at a frequency at which the vibrating head resonates in a vibration mode accompanied by deformation of the cylindrical hole in a direction perpendicular to the longitudinal direction,
The air layer of the liquid receiver is an integer of 1/4 of the wavelength obtained by the frequency and sonic velocity of driving the ultrasonic vibrator from the region where the vibration head resonates and becomes an antinode of the vibration of ultrasonic waves. Ultrasonic cleaner located at double the distance. In claim 9,
The ultrasonic transducer is driven at a frequency at which the vibrating head resonates in a vibration mode accompanied by deformation of the cylindrical hole in the longitudinal direction and a direction perpendicular to the longitudinal direction,
Of the bottom of the cleaning tank, at least the region where the vibrating head is projected in the vertical direction is made of a material having the resin as a main component,
In at least the area under the cleaning tank where the vibrating head is projected in the vertical direction, the frequency and the speed of sound that drive the ultrasonic transducer from the area that is the antinode of the vibration of the ultrasonic waves generated by the resonant vibration of the vibrating head. An ultrasonic cleaner in which the air layer or the metal member is provided at a distance that is an integral multiple of 1/4 of the wavelength obtained by. In claim 9,
An ultrasonic cleaner having a pipe for supplying water for cleaning the cleaning tank to a side surface of the cleaning tank. An ultrasonic cleaner according to any one of claims 1 to 12,
A sample dispensing mechanism having a nozzle for sucking the sample,
A control unit for controlling the ultrasonic cleaner and the sample dispensing mechanism is provided,
The controller cleans the nozzle by inserting the nozzle into the cylindrical hole of the vibrating head of the ultrasonic cleaner and driving the ultrasonic vibrator of the ultrasonic cleaner at the frequency. Automatic analyzer for performing. An ultrasonic cleaner according to claim 7,
A sample dispensing mechanism having a nozzle for sucking the sample,
A control unit for controlling the ultrasonic cleaner and the sample dispensing mechanism is provided,
An automatic analyzer that cleans the vibrating head by discharging water toward the vibrating head of the ultrasonic cleaner from a pipe provided on the side surface of the cleaning tank at a timing other than the inspection mode. An ultrasonic cleaner according to claim 12,
A sample dispensing mechanism having a nozzle for sucking the sample,
A control unit for controlling the ultrasonic cleaner and the sample dispensing mechanism is provided,
An automatic analyzer that cleans the vibrating head by discharging water toward the vibrating head of the ultrasonic cleaner from a pipe provided on the side surface of the cleaning tank at a timing other than the inspection mode.

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